Compressor



M. ARNOUIL v COMPRESSOR June 7, 1955 4 Sheets-Sheet 1 Filed Dec. 1, 1950K mew HWAJQLOuJ/L June 7, 1955 Filed Dec. 1, 1950 Fig. 2

4 Sheets-Sheet 2 June 7, 1955 ARNOUlL 2,710,137

COMPRESSOR I Filed D80. 1, 1950 4 Sheets-Sheet 52 as 52 f] Znue127bo zUnited States Patent Ofiice 2,710,137 Patented June 7, 1955 2,710,137COMPRESSOR Maurice Arnouil, Cosnac, near Brive, France, assignor toSociet'e Anonyme dite: S. E. P. A. Societe dExploitation des ProcedesArnouil, Cosnac, near Brive, France, a corporation of the FrenchRepublic Application December 1, 1950, Serial No. 198,565 Claimspriority, application France December 8, 1949 3 Claims. (Cl. 230-172) Myinvention relates to a compressor for use more particularly forrefrigerating purposes and which is especially designed with a view. tomake it more compact while decreasing the cost of its manufacture andimproving its cfiiciency. 2

Owing to such a special design of my compressor and first of all, thecold-generating agent .is allowed to flow through all themovable partstogether with a very small percentage of lubricant at such a rate that astrong and complete cooling of the parts of the compresspr is securedthroughout the range of working speeds. l p

My compressor is characterized moreover by the arrangement of thepitman-piston system and more partieularly that arrangement in .whichthe piston is designed as a spherical segment. l

In a particular embodiment of my invention thes'inglebearing compressoris equippedwith de oiling means belonging' to 'the compressor headstructure.

Two embodiments of the compressor according to my invention will nowbedescribed by way of example, reference being had to the drawingsappended hereto, in which:

Figure l is a cross-sectional view of the compressor;

Figure 2 is a sectional view of the same taken on its axis of rotation;

Figure 3 is a cross sectional view taken on line B-B of Fig. 4 and showsa modification of the compressor which more particularly comprises onesingle bearing and de-oiling means which belong to the structure of thecompressor head;

Figure 4 is a sectional view of the arrangement shown in Figure 3 takenat right angles thereto.

In the embodiment illustrated in Figs. 1 and 2 the compressor comprisesa casing 1 made of cast iron or any similar non-porous material and inwhich the rear bearing 2 is housed; a cover 3 in which the front bearing4 is housed is on the one hand bolted (not shown) on the said casingwith the interposition of a packing 5 and on the other hand fitted onthe cover of an electric motor 7 by means of screws 6.

Rotatably mounted in the front and the rear bearings 4 and 2 is theeccentric 8 which is coupled with the motor shaft 9, yet not keyedtherewith, by means of a cone 10 formed on said shaft.

The compressor is made fluid-tight at its motor end on the one hand by aring 11 fitted on the shaft 9 and slidably engaging the eccentric 8 anda packing ring 12 made of synthetic rubber or the like which isinterposed between the ring 11 and the cover 3 and on the other hand bya system composed of a ball 13, a ball stop 14 and a spring 15 adaptedto press the ring 11 against the eccentric 8.

The movable parts are balanced with the aid of a flywheel 16 secured onsaid eccentric 8 by a screw 100.

The system composed of the pitman 17 and the piston 18, to be describedhereinafter, is actuated by the eccentric 8; the piston moves within thecylinder 19 fitted or directly bored in the compressor casing; saidcylinder 19 receives a valve-supporting plate 20 with the interpositionof a packing 21.

A drop-forged steel compressor head 22 is secured by means of bolts 23on the compressor casing with the interposition of a packing 24;arranged between said packing and the valve-supporting plate 20 isspring steel valve 25.

The compressor head 22 is divided into two chambers, viz.: on the onehand the compression chamber 26 to which the pipe 27 is connected and onthe other hand the cooling chamber 28 to which are brazed pipes 29 and30. The three pipes just mentioned are connected with the condenser bymeans to be described hereinafter.

The only parts to be moved by the motor shaft are the pitmanpistonsystem 17-18 which is assembled to one single unit and the eccentric 8.

According to a characteristic feature of my invention the piston 18consists of a spherical segment cut from a sphere the diameter of whichis equal to the bore of the cylinder 19, said spherical segment beingobtained by cutting the sphere by two parallel planes that areequidistant from a plane perpendicular to the axis of the pitman andwhich are sufiiciently remote from said diametrical plane so that evenin the most tilted positions of the pitman relatively to the cylinderaxis, the piston is at every time in engagement with the chamber wall incylinder 19 along the circumference of a great circle of the sphere,which engagement by itself provides for a leakless joint. 7 Friction isthus minimized and the driving power necessary is decreasedcorrespondingly. Preferably,-for the sake of lightness of the unit, thepiston ishollowed out. l wLubrication of all the parts in motion iseffected continuously under the pressure prevailing on the suction sideof the compressor, the lubricant being renewed uninterruptedly.

With this end in view, the cold-generating agent is let in together witha small amount of continuously renewed lubricant which will reach allthe movable parts while the cold-generating agent sucked. at atemperature close to the expansion temperature will effectively cool thesaid movable parts and keep the lubricant at such a low temperature thatits qualities will remain unimpaired.

In this way, the lubricant is distributed quite uniformly amongst andover the working parts, whereby the amount of lubricant present in thecircuit. The additional advantage is thus obtained that the heatexchanges in the remainder of the circuit are not interfered with andthat the overall cold-generating efiiciency is increased while all theinconveniences which might result from the admission of an unduly highamount of lubricant into the circuit are removed.

The operation of the compressor is as follows:

As a result of the reciprocatory motion of the piston an intimatemixture of cold-generating agent with lubricant (which for the sake ofsimpleness will be referred to as gas" hereinafter) is sucked and thenforced into the compression chamber 26. The said gas enters the casingthrough the orifice 31, flows through the strainer which is made of wiregauze layers inserted in a recess 33 in the rear bearing 2, then throughthe orifices 34 in said bearing, thence through annular groove 35 inwhich it is divided for the first time, a small amount of gas huntingits way through a groove 36 to lubricate the bearing before it spreadsinto the compressor casing.

The remainder of the gas flows through the orifices 37, lubricates theball 13 and the stop 14 of the same and thenis divided once more intotwo unequal branches of which the one flows through channels 38 into theannular groove 39 in the pitman 17 and thence through a groove 40 intothe compressor for the purpose of lubricating the connecting rod bycooperating with the eccentric 8; the remainder of the gas flows througha channel 41 and is in turn divided, part of it flowing through theorifice 42 into the annular groove 43 in the front bearing 4 and thenceinto the compressor casing through the groove 44 in said bearing whichis lubricated thereby; the remainder of the gas enters the chamber 45 ofthe packing gland which it lubricates by flowing around it and flowsback into the compressor casing through an orifice 46.

The gas thus distributed throughout the compressor casing is sucked bythe piston 18 and flows through the ports 47 in the cylinder 19 into thesame.

Delivery is accomplished in the following manner: The gas compressed bythe piston is forced through the orifice and lifts the valve by whichduringsthe downward stroke of the piston the suction circuit is severedfrom the delivery circuit. The gas under pressure enters the compressionchamber 26, flows through a plpe 27 into a firstcondenser in which partof it is liquefied, thence through pipe 29 into the cooling chamber 28,is vaporised by exchange of heat with the compression chamber 26 whilecooling the latter and flows out through pipe 30 into an additionalcondenser whence the L shape of a spherical segment, similar to the arrhhggnlent illustrated in Figs; 1 and 2. V 7 a Housed in'the casingdefiningcompressor head 1' and integral therewith is a de-oiling devicecomposed of a' wire gauze packing a portion -of' which is arranged in achamber 51- provided between the 'outer casing of the head and atubularpartition 52 while the other. portion 1 is arranged in'a furtherchamber53 provided insidethe former 'and'oommunicating therewith throughapertures 54in said partition 52. r

Provided in the partition 56 between the compressor cylinder 19' and thede-oiling device are ports 57 closed bylaminar valves 58 the loadingsprings 59 of which are rested on a dish 60 housed in the chamber 61defined by the partition 62. interposed between said dish 60 and thepartition 62 is a spring 63- the force of which exceeds that of thevalve springs 59, and apertures 64 set the chamber 61 into communicationwith the annular chamber 51.

The fluid supplied to the compressor is admitted through the pipe 65,the lubricant contained in the recep tacle is carried along with thefluid through channels 66 into a channel 67 whence the intimate mixtureof cooling agent and lubricant enters chamber 68 from which it is ledthrough the oil grooves 69 into the top portion of the cylinder whenceit enters the de-oiiing device through the apertures 57 while liftingeither the valves 58 alone when the workingconditions are normal orboththe said valves 58 and the dish when lubricant is present in excess. Thegas-lubricant mixture is led through the apertures 55 into the chamber51 of the de-oiling device in which the gas is stripped from thelubricant which is retained by the wire gauze; the deoiling processis-made complete as the gas is flowed through the wire gauze pack 53',whence it is led through the pipe 70 into the cold-generating circuit.

t Sin'ce the discharge pressure is higher than the suction pressure, thelubricant retained in the de-oiling device oozes through the capillaryduct 71 into the receptacle 50.

Not only does such an arrangement afiord the advan tage of limiting theoil cycle to the compressor proper, the oil being prevented from gettinginto the cold-generating circuit, but the cooling area of the compressorhead is increased since part of its capacity is availed of to providethe de-oiling means, which ensures a better cooling of the valves; thecooling etfwt is enhanced by the provision of ribs 72 on the outside.

The use of a piston having the shape of a spherical to the axis ofthe'cyliiider; the pis'thn 1 casing arranged perpendicularly with respecI pressorshaft, an eccentric keyedonthecompressbi" shaft,

segment, which provides one of the features of my invention, ensures anoiseless working and provides for an absolutely fluid-tight jdintbetween the piston and the cylinder; in addition, as shown by practice,it makes it possible to make the head simply of sheet steel instead ofcast iron or steel and thereby to considerably decrease themanufacturing costs.

A compressor designed according to my invention for use in refrigeratingmachines does notexceed the dimensions of a 10 x 15 x 9 cms.parallelepipedo'n and its weight is no more than 2.1 kgs. At equalcooling effect the power consumption is not higher than 3& H. P, whereas/6 to 5/5 H. P. is necessary with compressors known up to the present. 1

I claim: I,

1; A compressor particularly for use in refrigerating machines whichcomprises, a casing arranged at the end of the shaft of a prime mover, ashaft mounted in the compressor casing, a compression cylinder withinthe casing arranged perpendicularly with respect to the'compressorshaft, an eccentric keyed on the compressor shaft, a pitrnan actuated bysaid eccentric, and'a'""pistori"rigid with said pitman slidably receivedin said cylinder, said piston consisting of asphericalsegmentbelongingto a sphere equal in diameter to the bore of-theicylinder, saidspherical segment be'ingdefined parallel lanes which are equidistantsphere perpendicular f'fthe fp sutiiciently remote" from diametrica'l ineven in the most tilted position's 'f a pitm re the cylinder along acomplete equatori umference.

2. A compressor particularly for n'efrige'rating machineswhichcomprisesga casing mange-La ar end of the shaftbfa rirnefifiov i Tcompressoricasing,

tto thecoma pitman actuated by said eccentric, a piston rigid 'with saidpitman slidably received in said cylinder, said piston consisting of aspherical segment belonging to a sphere equal in diameter to the bore ofthe cylinder, said spherical segment being defined by two parallelplanes which are equidistant from a diametrical plane of said sphereperpendicular to'the axis of the pitman and are sutiiciently remote fromsaid diametrical plane so that even in the most tilted positions of thepitman relatively to the axis of the cylinder, the piston is in contactwith the cylinder along a complete equatorial circumference, an oilreceptacle within the compressor casing, means in communication withsaid oil receptacle defining a passageway for fluid for circulating amixture of the gaseous fluid subjected to compression with a smallamount of lubricant for the compressor parts, a de-oiiing device withwire gauze immediately above the cylinder and integral with the casing,and a duct communicating with said de-oiling device and the oilreceptacle for leading the lubricant from the de-oiling means back intothe oil receptacle.

3. A compressor particularly for use in refrigerating machines whichcomprises, a casing made of'relatively thin sheet metal and arranged atthe'end of the shaft of a prime mover, a shaft mounted in the compressorcasing, a compression cylinder within the casingarranged'perpendicularly with respect to the compressor shaft, 'an

eccentric keyed on the compressor shaft, a pitinan actuated by saideccentric, a piston rigid with said pitman slidably received in saidcylinder, said pistonfconsistiiig of a spherical segment belonging to asphere equal in diameter; to the bore of the cylinder, said sphericalsegment being defined by two parallel planeswhich are equidistant from adiametrical plane of said sphere perpendicular to the axis of thepitma'n and are sufliciently remote from said diametrical plane so thateven in most tilted positions of the pitman relativelyto axis of thecylinder, the piston is in contact with the cylinder along a completeequatorial circumference, an oil receptacle within the compressorcasing, means in communication with said oil receptacle defining apassageway for fluid for circulating a mixture of the gaseous fluid sub-5 jected to compression with a small amount of lubricant for thecompressor parts, a de-oiling device with wire gauze above the cylinderand integral with the casing, and

a duct communicating with said de-oiling device and the oil receptaclefor leading the lubricant from the de-oiling 10 means back into the oilreceptacle.

References Cited in the file of this patent UNITED STATES PATENTS1,467,066 Prellwitz Sept. 4, 1923 15 6 Twardowsky Dec. 4, Spreen May 6,Keema July 8, Spohrer Apr. 16, Crowley Dec. 10, Drysdale Feb. 25, KingDec. 29, Rawson Feb. 7, Dalrymple Jan. 30,

